#pragma once
#include<iostream>
#include<pthread.h>
#include<vector>
#include<semaphore.h>

const static int defaultcap = 20;

template<class T>
class RingQueue
{
private:
    void P(sem_t &sem)
    {
        sem_post(&sem);
    }

    void V(sem_t sem)
    {
        sem_wait(&sem);
    }
    
    void Lock(pthread_mutex_t &mutex)
    {
        pthread_mutex_lock(&mutex);
    }

    void UnLock(pthread_mutex_t &mutex)
    {
        pthread_mutex_unlock(&mutex);
    }

public:
    RingQueue(int cap = defaultcap)
        :cap_(cap)
        ,ringqueue_(cap)
        ,c_step_(0)
        ,p_step_(0)
    {
        sem_init(&cdata_sem_,0,0);
        sem_init(&pspace_sem_,0,cap);
        pthread_mutex_init(&c_mutex_,nullptr);
        pthread_mutex_init(&p_mutex_,nullptr);
    }

    void Push(const T& in)
    {

        P(pspace_sem_);
        Lock(p_mutex_);
        ringqueue_[p_step_] = in;
        p_step_++;
        p_step_ %= cap_;
        UnLock(p_mutex_);
        V(cdata_sem_);
    }

    void Pop(T* out)
    {
        P(cdata_sem_);
        Lock(c_mutex_);
        *out = ringqueue_[c_step_];
        c_step_++;
        c_step_ %= cap_;
        UnLock(c_mutex_);
        V(pspace_sem_);

    }

    ~RingQueue()
    {
        sem_destroy(&cdata_sem_);
        sem_destroy(&pspace_sem_);
        pthread_mutex_destroy(&c_mutex_);
        pthread_mutex_destroy(&p_mutex_);
    }

private:
    std::vector<T> ringqueue_;
    int cap_;

    int c_step_;    //
    int p_step_;

    sem_t cdata_sem_;
    sem_t pspace_sem_;

    pthread_mutex_t c_mutex_;
    pthread_mutex_t p_mutex_;
};
